"Nothing more than a bunch of drink-ravaged show-offs who can't be bothered learning lines so they just turn up and wing it" is how one Improviser describes Friday's entertainment.

But anyone who's seen Whose Line Is It Anyway?, the hit TV programme whose alumni include all this show's participants, will know there's a lot more - and a lot more laughs - to improvised comedy than that.

Led by the very tall and very loud Steve Frost and consisting of some of the country's most time-honoured comedians, The Improvisers have performed everywhere from London's Comedy Store and the Glastonbury Festival to Hong Kong and Singapore in the past few years.

Previous shows have covered performance styles as diverse as Shakespeare and Film Noir, depicting everything from a bunch of patient-less dentists to George Bush searching for the Brooklyn Bridge.

But there's no telling what will happen tomorrow - this is a show where the content and direction is decided entirely by audience heckles.

Much like Whose Line Is It Anyway? but without the safety net of the editing suite, The Improvisers use a series of games and exercises to kick-start an evening of pure comedy ranging from satirical to musical, verbal to physical.

As the participants strive to keep a comedic ball in the air without director or script, it's part stand-up, part spectator sport.

"Between us we have about 188 years of improvising experience," says Frost of his touring team, which features veterans Andy Smart and Steve Steen, pianist Richard Vranch and the fantastic Jim Sweeney, who, having been diagnosed with multiple sclerosis in 1990, received blanket acclaim for his recent show My MS And Me.

With his mad eyebrows and inane grin, Frost himself became a favourite on Whose Line Is It Anyway?, where he excelled at the physical comedy of games such as Old Job, New Job and did hysterically badly at more verbal challenges such as Number Of Words, regularly causing host Clive Anderson to bawl that "the idea is to speak in sentences of three words, not say three words and then stop!"

Working with Frost, say his team mates, is like "improvising with a big friendly dog".

Joining The Improvisers for the Brighton show will be special guest Phill Jupitus, who got involved with the team at one of their annual Glastonbury shows and, as a team captain on Never Mind The Buzzcocks for nearly ten years, has had plenty of experience at off-the-cuff comedy.

"People think that programme is all scripted," he says, "but me and Bill Bailey are always looking for the comedy within the show that can only happen spontaneously.

"Something I hadn't done before was to work in a team but with The Improvisers it's great because they're all so brilliant. The hardest bit is just keeping a straight face."

Starts 8pm, tickets cost £15. Call 08700 606650.